Snap fastener



Sept. 8, 1953 J. F. LYNCH 2,651,093

- SNAP FASTENER Filed Feb. 5, 1950 1/ A ]Z I IN V EN TOR.

, Jam Flyncfi Patented Sept. 8, 1953 .i

UNITED. STATES P T; OFFICE v. p .lSN rj Nsaf r James F. Lynch, Los Angeles, Caliifi, assignorto United States Rubber Com'panmaNew :York, V ,N. Y.',acorporationoi'NewJei-sey 1 I Application Februaryfl, 1950, s ri 1 No. 4L2,2a0

I This invention relates to animproved detachable snap fastener comprising a metal plate to which a stud is adapted to be attached and detached by deflecting portions of the'plate-along an elongated slot within which the stud may be secured." Y '1 9 The invention is particularly adapted for securing a flexible container, suchas the bladder type of fuel cell, in the cavity provided therefor in the wings, or fuselage, of an aircraft. For that use the stud is attached to'thecell wall and the stud is detachably secured to the plate which in turn is permanently attached to the wall of the cavity which supportsthewall of the cell. A requirement of the fastener is that the stud-may be readily attached to-and detached from the plate to permit installing and replacing the fuel cell quickly. The fastener also should be capable of securely holding the cellto the walls of the cavity to prevent the collapse of the cell or excessive relative movement thereof with respect to the supporting wall under allconditions encountered in the operation of the aircraft.

Heretofore quickly detachable fasteners/have been used for securing the walls of'the fuel cell to the'walls of its supporting cavity. Such'prior fasteners sometimes became detached due tothe shifting of the fuel load in the cell andalso-because of a sub-atmospheric pressure being pro duced in the cell by the discharge of fuel from an improperly'vented cell, which caused thecollapse of the cell and the disengagement of the fastener;

The improved fastener embodying this invention is more effective for securing the cell-in place and is less costly than the prior fasteners heretofore used. The fastener comprisesthe combination of a stamped thin metal plate and a stud attached thereto. The fastener plate has a well stamped therein, which is provided with a bottom and a flange extending from the rimof the well for securing the plate'to the supporting wall of the cavity for the cell. The stud is provided with a head which is connected by a smaller neck to a shoulder which is larger than the head. Such members cooperate with a keyhole slot in the bottom of the well. The stud issecured to the plate by extending the head through the larger end of a keyhole slot, which excludes the shoulder. The neck is then extended into the narrow branch of the slot which excludes the head and shoulder. The stud is thus held in its attached position by the projection of the edges of the slot between the head and shoulder of the stud. Relatively deflectable'portions are form'ed in the bottom of the well'atdifferent levels on l2 cam- (01. 2442;)

each side'of narrow branch of the slot.v The distance between the levels :in respect to the depth of the well is slightly'greater than the dis-,

tance between the head and shoulder of the stud. Such portions of the bottom are relatively deflectedby the head and shoulder of the studas the stud passes into or from its fully attached position. After-thestudhas passed into its attached position, the deflected portions spring back totheir undefiected positions and restrain the stud from being disengaged from the plate.-

However the stud may be quickly detached from the plate by proper manipulation and upon ap.-,

plying properly directed force to deflect the por-I tions of the well bottom at the different levels.

In the preferred-form of the invention the bottom of the plate is provided with an incline which extendsfrom one of the levels to the other,. and insuch embodiment the fastener stud is restrained from being detached from its attached position by threeforces: (a) a force that is re-" quired to tilt theaxis of the stud fromits static loaded position, (12) a force that is required to overcome the force of gravity exerted on the stud to move-its head-up the incline between the portions of-the bottom at the different levels, and (c) a force that is required to deflect the portions of the bottom of the well at the different levels relatively with respect to each other upon the application of the first two forces. Since such forces are required to be exerted on the stud to removeitfrom the attaching plate, it provides a greater security than the prior fasteners. Also, since the bottom of'the well provides the-snap acting deflecting member for retaining the stud inits attached position' no extraspring member isrequired, and by the elimination of such extra par-t the manufacture of the fastener is simplified and can be made at less cost.

' The invention will be further; described in reference to the accompanying drawings, in which: 'Fig. l-is a plan view of the fastener attachin plate fembodyingthis invention, and it is shown as'secured to' the top of thesupporting cavity for ihai e 'eellfl j' v is -a' 'sideelevational view' of the attaching platefshown in Fig. ;l; Fig. 3 'is "a-cro"s's sectional view on line 3-3 of Fig. l, and showing in addition 'a cross sectional view of the fastener attaching stud as it begins to engage the attaching plate; Fig.4 is a view similar to Fig. 3, but showing th'erelationshipbetween the fastener stud and the fastener platefwhen the portions of different Fig. 5 is a view similar to Figs. 3 and 4, but showing the position of the fastener stud when it is in its fully attached position and the different levels of the bottom of the well have sprung back to their undefiected positions.

As shown in Fig. 3 of the drawings, this invention is illustrated herein in connection with a fuel cell for the purpose of attaching walls v Hi to the supporting walls I I of the cavity for the fuel cell, which may be formed in the wings or fuselage of an aircraft. The fastener comprises. a, stamped thin sheet metal plate 12 which is riveted, or otherwise secured to the cell supporting structure. The wall In of fuel cell is secured to the fastener stud =l'3,"w'hich is provided with a stem I4 extending into the insideof the cell, and it is adapted to be attached and detached from the fastener plate 12 by a workman who operates from stud stem 14 is provided with a head l5, which is attached to a flange or shoulder l6 bya neck H. The stem Id of the stud extends through an opening 18 in the wall of the cell, and th wall 'is clamped with a fluid tight seal between the shoulder 16 and a flange IS on a sleeve 20 by a nut 2!, which is screwed down on the threaded stem l3 against the sleeve 20.

The fastener plate 12 for example may be made. out of thin sheet aluminum metal having a t i kness of .028 inch. It has a well 22 stamped therein, which is provided with a bottom -23,.and

attaching flange 24,.through which rivets 25 are passed to secure the plate to the cell supporting structure H. The bottom 23 of the well has av key-hole slot 26 formed therein, which has an enlarged circular opening 21 at one end and a narrow branch opening 28 extending therefrom, which terminates in a slightly enlarged opening 29. The bottom 23 is formed on two levels 30 and 3|, which are connected by an inclined step 32, which extends transversely, of the narrow branch 28 of the key hole slot. The difference in the elevations of the levels is slightly greater than the length of the stud neck 11. The larger opening. 2'! of the slot is formed in the upper level 3! of the bottom 23, and the narrow branch 28 terminates inthe lower level 30 of the bottom 23.

The stud I3 is manipulated by the hand of an operator from the inside of the cell l0, which may be provided with a hand hole, through which the 'workmans handv may be extended, or which may be provided with an opening large enough for the workman -to crawl through to the inside of the cell. In order to attach the stud 43 to the plate l2, the workman grasps the stem 14 of the stud with his hand, and inserts its head [:5 through the enlarged opening 21 in the key hole slot, and brings the stud into position as shown in Fig. 3. In such. position, the head [5 is extended into the well 22, and the shoulder 18, which is larger than the opening 21. abuts against the outside of the bottom 23 on an incline between the upper level 3t and he; lower level 30. The neck 11 of the stud I3 is then pushed in the direction of the step 32 and into the narrow branch 28 to the position shown in Fig. 4.. The length of the neck I! is less than the height of the step 32, and as the rounded edge of the head 15. makes contact w'th the top of the step 32, it rides over the upper edge of the step and defiects the incline step. 32 between the head l5 and the'shoulder l6 of the stud. Theoperator must exert pressure on the stud. in the lengthwise direction of the narrow slot Rim-order todeflect 4 the edges of the step to force the overlapping area of the head and the shoulder [6 over the step 32. After the overlapping areas of the head and shoulder have cleared the step 32, the edges of the step 32 spring back to their undeflected positions and thereby restrain the stud from returning towards the opposite end of the slot 26. When the stud has been moved to its fully attached position, it occupies the position shown in Fig. 5. In such position, the neck 11 of the stud I3 may wander around in the closed end 29 V Y of the branch opening 28 (which is slightly larger than the neck ll) to permit the cell wall 10 to adthe inside of the cell. The L just itself and relieve stresses thereon.

Where the attaching plate i2 is secured to the top wall of the supporting cavity l I, the force of gravity acting upon the wall ll) of the cell normally acts to'prevent the disengagement of the stud from the plate. The same is also true when the plate is attached to the side walls of the cell cavity where the narrow branch 28 of the slot extends downwardly. In order to disengage the stud, it must be, turned through an angle as shown in Fig. 1, and the force of gravity acting on the wall it] must be overcome to force the head 15 of the stud up the inclination of the step 32, and at the same time additional force must be applied to deflect the upper and lower levels of the bottom to cause the stem H to pass through the narrow passage 28 into the enlarged opening 21 in the slot, through which the stud head l5 may be removed. It. will thus. be understood that several forces are required to be applied in given directions in order to. remove or disengage the stud l3 from the attaching plate 12.

Whilethe details of this invention have been described herein, it will be understood changes may be made therein without departing from the spirit of the invention or the; scope'of the appended claims.

Having thus described my invention what .I claim, and desire to protect by Letters Patent is:

l. A snap fastener comprisingm combination a thin sheet metal plate and a stud adapted to. be detachablyconnected to said plate, said stud having a head connected to a shoulder by a neck, said plate having a well stamped therein; an attaching flange extending fromthe perimeter ofsaid well, a bottom in said well having upper and lower levels-connected by an inclined step,

said bottom having a slot therein provided with a narrow portion extending transversely through the lengthof said step, said slot having an enlarged end located within said upper level of said bottom and the opposite end of said slot terminatingin said lower level of said bottom at a distance from said step greater than one half of the sum of; the dimensions of said neck and head extending perpendicular to the length of said neck, said shoulder of said stud being larger than said head. said enlarged end of said slot being adapted to receive said head and exclude said shoulder, said narrow portion of said slot being adapted to receive said neck and exclude saidhead and shoulder, the height of said step being greater than the length of said neck, said step being adapted to be deflected by the pressure exerted thereon between said head and shoulder when said head is. above said step, and said step being adapted tospring back to its undeflected positionafter the passage of said head over said step, and thereby restrain the return of said neck of said stud to the opposite end of said slot.

2. A snap fastener comprising in combination athin sheet metal plate and a stud adapted to be detachably connected to said plate, said stud having a head connected to a shoulder by a neck, said plate having a well stamped therein, an attaching flange extending from the perimeter of said well, a bottom in said well having upper and lower levels connected by an inclined step, said bottom having a slot therein comprising relatively small and large enlargements at each end thereof connected by a narrow portion extending transversely through the length of said step, said small and large enlargements being located respectively within said lower and upper levels of said bottom and the end 01 said slot at the smaller of said enlargements terminating in said lower level of said bottom at a distance from said step greater than one half of the sum of the dimensions of said neck and head extending perpendicular to the length of said neck, said shoulder of said stud bein larger than said head, the larger of said enlargements being adapted to receive said head and exclude said shoulder, said narrow portion of said slot and the smaller of said enlargements being adapted to receive said neck and exclude said head and shoulder, the height of said step being greater than the length of said neck, said step being adapted to be deflected by the pressure exerted thereon between said head and shoulder when said head is above said step, and said step being adapted to spring back to its undeflected position after the passage of said head over said step, and thereby restrain the return of said neck of said stud to the opposite end of said slot.

JAMES F. LYNCH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 229,617 Laflin July 6, 1880 540,308 Hamburger June 4, 1895 1,037,499 Lecoutre Sept. 3, 1912 FOREIGN PATENTS Number Country Date 149,780 Great Britain Aug. 20, 1920 

